Advances in drilling technologies, including systems capable of drilling extended reach horizontal wells, have increased the need for “real time” petrophysical answers during the drilling process. To optimize well placement/design and/or the drilling process, it is important to have as much knowledge as possible regarding petrophysical parameters associated with the subsurface formation being drilled, such as the porosity, permeability, and hydrocarbon/water saturation of the formation. Measurement-while-drilling nuclear spectroscopy devices have made possible the calculation of such petrophysical parameters during the drilling process.
For this reason, it would be of great benefit to be able to provide a method of using nuclear spectroscopy measurements to determine a petrophysical parameter associated with the subsurface formation being drilled and then to use this petrophysical parameter to determine a drilling parameter during the drilling process.